Spark-plug.



A. SCHMIDT.

SPARK PLUG.-

APPLICATION FILED JULY 29.1916.

Patented Oct. 2, 1917.

1,241,5fiQ.

4 a WW WMr M abtommz S A1PATENT oration ALBERT SCHMIDT, 0F FLINT, MICHIGAN, ASSIGNOR TO CHAMPION IGNITION COM- PANY, OF FLINT, MICHIGAN, A. COBPOBATION OE MICHIGAN.

SPARK-PLUG.

To all whom it may concern:

Be it known that I, ALBERT SCHMIDT, a citizen of the Republic of France, residing at Flint, in the county of Genesee and State of Michigan, have invented certain new and useful Improvements in Spark-Plugs, of which the following is a specification, reference being had therein to the accompanying drawings.

The invention relates to spark plugs designed for use in connection with high-speed internal combustion engines, and the invention comprises various features of-construction as hereinafter set forth.

In the drawings:

Figure l is a longitudinal section through the plug;

Fig. 2 is a cross-section on line w-m Fig. 1; and

Fig. 3 is a perspective view of the member forming the grounded electrode.

A is the outer casing provided with the usual threaded nipple B. C is an insulator in the form of a tube or hollow cylinder fitting within the inner portion of the casing A. D is a separate insulator fitting within the outer portion of the casing and secured therein by suitable means, such as an enlargement E engaging reverse shoulders F and G on the casing. H is an electrode passing through the outer insulator D, having an enlargement I extending between outer and inner insulator and aportion J fitting within the inner insulator. This electrode is formed of material which is relatively high in heat conductivity. K is an inward extension of the electrode formed of a material having a high-fusing point. L is a grounded electrode, which has an annular portion L seated upon the inner end of the annular insulator O and also provided with a projecting point L. M is an insulator-sleeve preferably formed of mica,

which surrounds the inner and outer insulators, bridging the gap therebetweenand lying adjacent to the inner wall of the easing. N are heat radiating fins secured to the outwardly-projecting portion of the electrode.

In assembling the parts just described, the outer electrode is fixedly secured. preferably by hot fashioning metal which forms the opposed shoulders F and G, to make a mechanical and gas-tight joint. A gas-tight joint is formed between the enlargement I of Specification of Letters latent.

Patented (Oct. 2, E9153,

Application filed July 29, 1916. Serial No. 112,038.

the electrode and the end of the inner annular insulator by lapping, and a gas-tight seal is also formed between the opposite end of the annular insulator and the inner end of the casing with the annular portion L of the electrode arranged therebetween. This 'may be accomplished by hot pressingthe' metal forming theinner end of the case to overlap said annular insulator and electrode.

casing which is in good heat conducting connection with the water-jacket, there will be a rapid dissipation of the heat. Leakage of gas is prevented by the sealed joints at opposite ends of the annular insulator,'and the heat imparted to the electrode, as well as a portion of that to the insulator, will be conducted outward through the shank of the electrode and dissipated by the radiating fins N.

In operation, the rate of heat dissipation is sufiiciently rapid to prevent rise in temperature of either the electrode or the insulator C to a point where pre-ignition will take place, while the length of the insulating surface between the electrodes is sufiicient to avoid danger of short circuiting.

What I claim as my invention is 1, In a spark plug, the combination with the casing, of an insulator secured in the upper portion of said casing, an electrode passing through said insulator and provided with an enlargement at the inner end thereof, a tubularv insulator seated at one end upon said enlargement of the electrode and forming a gas-tight seal therewith, and an inturned flange on said casing abutting against the opposite end of said insulator tube and forming a gas-tight seal therewith.

2. In a spark-plug, the combination with a casing, of an insulator secured in the outer] portion of said casing, an electrode passing through said insulator and provided with an at the inner end of said/casing overlapp ng and sealing the inner end of said tube, and an insulator sleeve surrounding the adjacent portions of the inner and outer insu1ators and bridging the gap therebetween.

3'. In a spark plug, the combination with a casing, of an insulator secured in the outer portion thereof, an electrode passing through said insulator and having an inteelectrode having an annular portion adja 15 cent to the inner end of said insulator tube, and an inturned flange on said casing for clamping said annular portion of the grounded electrode against the insulator and forming a gas-tight seal.

4:. In a spark plug, the combination with a casing, of an insulator secured in the outer portion thereof, an electrode passing through said insulator and having an' integral enlargement seated on the inner end thereof, an insulator tube within the inner portion of said electrode, having one end seated upon and forming a with the enlargement of sai electrode, a

(gas-tight seal grounded electrode having an annular portion contacting with the inner end of said insulator tube, a flange on said casing turned in upon said annular electrode and forming a gas-tight seal, and an insulator-sleeve surrounding adjacent portions of said inner and outer insulators and bridging the gap therebetween.

In testimony whereof I afiix my signature.

' ALBERT SCHMIDT. 

